<template>
  <div class="spec-preview">
    <img :src="skuImageList[defaultIndex]?.imgUrl" />
    <div class="event" @mousemove="mousemove"></div>
    <div class="big">
      <img :src="skuImageList[defaultIndex]?.imgUrl" ref="imgEle" />
    </div>
    <div class="mask" ref="maskEle"></div>
  </div>
</template>

<script>
export default {
  name: "Zoom",

  data() {
    return {
      defaultIndex: 0,
    };
  },
  mounted() {
    this.$bus.$on("getChangeImgId", (index) => {
      this.defaultIndex = index;
    });
  },
  props: ["skuImageList"],
  methods: {
    mousemove(e) {
      //获取鼠标距左上角的位置
      let left = e.offsetX;
      let top = e.offsetY;
      // console.log( e);
      // console.log( e.target.offsetLeft);

      //获取蒙版距左上角的位置
      const mouseList = {
        x: left - this.$refs.maskEle.offsetWidth / 2,
        y: top - this.$refs.maskEle.offsetHeight / 2,
      };
      //设置临界值

      if (mouseList.y < 0) {
        mouseList.y = 0;
      }
      if (mouseList.x < 0) {
        mouseList.x = 0;
      }
      if (
        mouseList.y >
        e.target.clientHeight - this.$refs.maskEle.offsetHeight
      ) {
        mouseList.y = e.target.clientHeight - this.$refs.maskEle.offsetHeight;
      }
      if (mouseList.x > e.target.clientWidth - this.$refs.maskEle.offsetWidth) {
        mouseList.x = e.target.clientWidth - this.$refs.maskEle.offsetWidth;
      }
      //修改蒙版的位置
      // console.log(this.$refs.maskEle.offsetHeight / 2);
      this.$refs.maskEle.style.top = mouseList.y + "px";
      this.$refs.maskEle.style.left = mouseList.x + "px";
      //修改大图的位置
      this.$refs.imgEle.style.top = -2 * mouseList.y + "px";
      this.$refs.imgEle.style.left = -2 * mouseList.x + "px";
    },
  },
};
</script>

<style lang="less">
.spec-preview {
  position: relative;
  width: 400px;
  height: 400px;
  border: 1px solid #ccc;

  img {
    width: 100%;
    height: 100%;
  }

  .event {
    width: 100%;
    height: 100%;
    position: absolute;
    top: 0;
    left: 0;
    z-index: 998;
  }

  .mask {
    width: 50%;
    height: 50%;
    background-color: rgba(0, 255, 0, 0.3);
    position: absolute;
    left: 0;
    top: 0;
    display: none;
  }

  .big {
    width: 100%;
    height: 100%;
    position: absolute;
    top: -1px;
    left: 100%;
    border: 1px solid #aaa;
    overflow: hidden;
    z-index: 998;
    display: none;
    background: white;

    img {
      width: 200%;
      max-width: 200%;
      height: 200%;
      position: absolute;
      left: 0;
      top: 0;
    }
  }

  .event:hover ~ .mask,
  .event:hover ~ .big {
    display: block;
  }
}
</style>